Comparison of newer Kane formula with Sanders Retzlaff Kraff/Theoretical and Barrett Universal II for calculation of intraocular lens power in Indian eyes

Abstract

Purpose: To compare the efficacy of Kane formula with Sanders Retzlaff Kraff/Theoretical (SRK/T) and Barrett Universal II in predicting intraocular lens (IOL) power in Indian eyes. Methods: This retrospective study conducted in a tertiary care eye hospital. Data from patients having uneventful cataract surgery with Tecnis ZCB00 IOL implantation were obtained from Lenstar and electronic medical records. Eyes were divided into subgroups based on axial length (AL) as short (<22.0 mm), medium (22–24 mm), and long (>24 mm). The predicted refractive outcome for each patient was calculated after optimizing the lens constant. Prediction error was calculated by subtracting the predicted spherical equivalent from achieved spherical equivalent 1 week post-surgery. The mean absolute error (MAE) and median absolute error (MedAE) and percentage of eyes within 0.25, 0.5, 1, and 2 D were calculated for each formula. Friedman test, Cochrane Q test were used for statistical analysis. Results: Out of the 350 eyes included in the study, we found that without lens constant optimization, Barrett formula performed better than SRK/T and Kane ( P < 0.0001). Over the entire range of axial lengths, Kane formula performed slightly inferior compared to Barrett and SRK-T, both of which performed equally well ( P = 0.006). On subgroup analysis, Kane formula performed inferiorly for medium eyes as compared to the other two. No significant differences were noted between the formulae for short and long eyes Conclusion: Kane formula did not outperform Barrett Universal II and SRK/T in Indian eyes.

Retrospective assessment of accuracy of nine intraocular lens power calculation formulae in eyes with axial myopia

“…However, they did not compare all the other formulas. Our results were different from those of Paritekar et al, [ 29 ] who found SRK/T and BU II to have lower MedAE and MAE than Kane formula for myopic eyes. This could be because they compared only 59 eyes in the myopic group (which they defined as AL >24 mm) and compared data at the end of 1 week instead of 1 month postoperatively.…”

Accuracy of new intraocular lens calculation formulas in Chinese eyes with short axial lengths

“…Our findings suggest that there were modest differences between the formulas tested, with refractive prediction errors of approximately 0.32 D on the myopic side with the Hoffer Q, Kane, SRK/T, and Holladay 1 formulas. Similar findings were reported by Paritekar et al ( 17 ) in their study. Thus, the recommended lens constant for the Tecnis IOL should be altered for optimization.…”

“…The Kane (MAE 0.441 D) formula was the most accurate predictor of postoperative refractions in their study. However, research by Paritekar et al ( 17 ) on Indian populations demonstrated that the Kane formula did not exhibit significant advantages in short AL eyes, which was consistent with our findings. In our study, the Kane formula also did not show clear advantages in short eyes.…”

“…All IOL formulas are based on data derived from clinical practice. In our study, the same IOL type was used as in the study by Paritekar et al ( 17 ). Moreover, the differences in racial characteristics may have contributed to the discrepancy.…”

A Study Linking Axial Length, Corneal Curvature, and Eye Axis With Demographic Characteristics in the Emmetropic Eyes of Bangladeshi People

“…Eyeballs are a cystic structure and almost spherical in shape [ 1 ]. The anterior and posterior diameter (axial length (AL)) is usually about 22-24 mm in the emmetropic eye [ 2 ]. The parallel rays of light from any image that enters the eye are focused on the retina by the refractive properties of the cornea and lens [ 3 ].…”